Preventing color formation in sulfonyl halides



nitcd States PREVENTING COLOR FORMATIONIN SULFONilL .HALIDES 14 Claims. *(Cl. 260-543) This invention relates to the treatment of saturated aliphatic and alicyclic sulfonyl :halid'es prepared by the Reed reaction. In onejparticula'r. aspect theinventionjper- 'tains 'to minimizing the color formation which is encountered in sulfonyl chlorides on standing. 7

The sulfochlorination reaction, often termed .the Reed reaction, has been applied to numerous'types (if-organic materials. By reacting organic compounds with a mixture of sulfur dioxide and chlorine, preferably at about room temperature with 'the aid .ofuultravioletslight, saturated aliphatic and alicyclic sulfonyl chlorides. are formed which can be represented diagrammaticallyby the structural formula:

na -oi I;

wherein R is the'residue of the organic .compound reacted, and is attached to the -SO,zCl group at an aliphatic or .alicyclic carbon atom. Sulfochlorination is :perhaps most-often applied to hydrocarbons, containing an aliphatic or alicyclic group, particularly paraflins. However, it is also applicable -to aliphatic and alicyclic esters, acids, acid anhydrides, ketones, .et hers, nitriles, chloroparaflins, polyethylene, silicones and alcohols. ?In view ofthe voluminoussliterature on thistype'ofreaction, to which reference -is.-herebyernade, :it .is deemed :unnecessary to go into great details :in the present application concerning organic materials which can "be .sulfochlorinated and procedures for effecting :this. See forsexamiple "PB167,-260, issued by 'Oflice of the Publication Board of the Departmentof Commerce, Washington 25, :=D.C., on the reactionof sulfur dioxide and chlorine .with-hydrocarbon :derivatives. The sulfochlorination reaction :has also recently :been extended by :me to -,nitroalkanes, :e. ;g.,

.nitromethane, 'as described :andclaimed inimycopending application, Serial .No. 140,158, filed January .23, T1959, now .U. S. Patent No. 2,718,495 issued September 20, 1955. It is well-knowniingtherart that the Reed reaction sulfochlorinates. only ontaliphatic or-alicyclic carbon =See Fox U. S. Patent 2,346,568. :See :also Fox U. 8. Patent 2,321,022 for sulfochlorinat-ion of the side chain only :in alkylaromatichydrocarbons, e. g.,-dodecylbenzene. The present invention is broadly applicable to -theitreatment of all such saturated aliphatic and alieycl-icsulfonyl halides. By way of specific example of compounds that :can be sulfochlorinated to give materials treatable by my inven- 'tion, there can be mentionedipropionic acid, caprylic acid, stearic acid, levulinic acid, glutaric acid, :propionic :acid anhydride, butyl stearate, hexyl adipa'te, :methyl ethyl rketone, cyclopentanone, n-butyl chloride, chlorocyclohcxane, butyl ether, lauryl alcohol, 'n-octanol, idodecylbenz'ene, propane, 2-methylheptane, icosane.

Upon"completion of the sulfochlorination reaction, 'color begins to develop in the resulting sulfo'nyl chloride material. In many instances the color formation is almost immediately apparent, and some materials may :be-

at'cnt 2,749,365 .Patented June 5, 1956 come quite dark-in only amatter :of hours. iOther-Zmore stable sulfonyl chlorides develop dark color only on standing for comparatively longer periods of time :such'as daysor weeks, but even these materials show some color formation very quickly. Since :-it is often desirable to store a sulfochlorinated material either for a 'short time or for long periods of time,'dependin'g upon the-intended use, it is apparent that colorformation' isa SEIiOUSiPlOb- .lem. To the best of my knowledge, rthis:pro"blem*has not heretofore been solved.

- object of this invention is to treat zsulfouyl rhalides .preparedby the Reed reaction. Another 'objectof the invention is to inhibit, minimize or prevent color formation in :such isulfochlorinated materials. 'A furthenob- 'ject is to provide treatment for such sulfochlorinated materials whichis simple, inexpensive and yet greatly inhibits *or completely prevents color fo'rmationon st'a'nding'for/long periods "of time. Further objects ai cl ad- 'vantages'of the invention will be apparent to oneskille'd in ithe art from the accompanying disclosure and discussion.

-Ihave found that color formation in aliphatic sulfochlorinated and=alicyclic-sulfochlorinated materials can 'be markedlydnhibitedand often prevented for'lon'g periods of time merely by giving such materials a light -treatmerit with analkaline material. According to preferre'd 'embodim'eiits of my-invention, sulfochlorinated organic materia'l's are, immediately after theirformation by the Reed sulfochlorination reaction, washed with an "aqueous alka'line solution at a temperature sufiiciently low, for a timeshort enough, and'at aconcentration-of alkaline material-low enough, to avoid substantial-hydrolysis or other reaction of thesulfonyl chloride, and inthe absence of other materials reactivewith the sul fonyl chloride at the treating conditions, and'then'stored. During this storage the 'sulfochlo'rinated organic material undergoes '.little or no color formation 'even though the "storage .period extends for months oryears. Although I 'do not wish to be bound by any theory, it is my belief that in the reaction of organic materials with a mixture of sulfur dioxide and chlorine, small amounts of a dark acidic ma- "terial-are formed in addition "to the desired suIfonyl chloride product. It is often observed that such dark material will precipitate from the reaction mixture on standing. I have analyzed this black material for sulfur and chlo- .rine and 'found it high in sulfur content but low in chlorine. It :is also strongly acidic, .and Ibelieveit to be a sul'fonic acid .or sulfinic acid type of material. .lt .-is my thought thatmyalkaline treatment removes this black .acidic material and that the latter or its decomposition .;products.arethe ordinary cause of color-formation-in sulfochlorinated materials.

The preferred type of alkaline reagent employed in the present invention for treating sulfochlorinated materials is an aqueous solution of an alkali metal hydroxide. Although all of the alkali metal hydroxides are suitable, sodium hydroxide and ,potassium hydroxidelare preferred becauseof-availability and cheapness. Another werydesirable type of alkaline treating .agent is an aqueous solution of an alkali metal carbonate or alkali metal bicarbonate. :Here again, although carbonates :and bicarbonates of all of the alkali metals are operable, sodium and potassium carbonates and bicarbonates are preferred. Furthermore, aqueous solutions of alkaline earth metal hydroxides, carbonates, or :bicarbonates can be used-in effecting the invention. The hydroxides, carbonates, and bicarbonates of all alkaline earth metals are operable, but those of calcium, strontium and titanium a-re preferred.

Although any :of the alkali metal and alkaline ezuzth metal compounds which are :alkaline reacting oan EbB used, and preferably as aqueous solutions as described above, those which are not very soluble in water can be used as slurries or suspensions in water. All of the compounds mentioned can also be used in the form of the solid provided the solid is wet with water or suflicient water is present in the system to obtain the desired colorstabilizing effect. Thus, for example, the sulfochlorinated material to be treated can be passed through a bed of solid pellets of sodium hydroxide which contain a few per cent water, or the required amount of water can be introduced in admixture with the sulfochlorinated material and the admixture passed through a bed of sodium hydroxide pellets or a bed of any solid basic-acting material.

Anhydrous ammonia effects some color stabilization, but the eflect is short-lived. An aqueous solution of ammonia can be employed to obtain the desired color stabilization. Furthermore, alkaline organic compounds, for example amines, can be used in accordance with the invention to impart color stability to sulfochlorinated materials. It must be noted however that in the use of ammonia or amines in accordance with the present invention, it is essential that the quantity of ammonia or amine be sufiiciently limited, and that the treatment conditions be sufficiently mild as to quantity and concentration of ammonia or amine and time and temperature, to avoid effecting any appreciable reaction of the sulfonyl chloride to form the corresponding sulfonamide. With alkanesulfonyl chlorides, there is likelihood of forming emulsions when treating with aqueous alkaline materials, particularly aqueous sodium hydroxide or potassium hydroxide. The treatment should therefore be sufliciently mild to avoid this.

It is preferred to effect the alkaline treatment of this invention at temperatures below 50 C., and usually below room temperature, e. g., below 20 C., on down to C. Ordinarily a time is used within the range of from one-half minute to one hour.

The following examples are given to illustrate some of the preferred methods of carrying out the present invention. It will be understood that the details of the materials used and proportions and treating conditions of these examples are by way of illustration.

Example 1 A paraflinic hydrocarbon liquid containing on the average of 16 carbon atoms per molecule was sulfochlorinated in a 1-liter, 4-necked, round-bottomed flask fitted to receive (1) an irradiation lamp, (2) a mechanicallydriven stirrer, (3) a combination inlet and outlet tube, and (4) a thermometer. Chlorine and sulfur dioxide gases were metered through flowmeters, mixed in a Y tube and fed through the side neck to the bottom of the flask. This inlet tube ended in a centered glass disperser. A 4-watt General Electric U-type germicidal lamp within the reaction flask and one inch above the liquid level was used as the ultraviolet light source. The spectrum of this lamp shows the strongest irradiation at 2537 Angstrom units and weak lines between 2300 and 2400 Angstrom units.

The material subjected to sulfochlorination in this example had a specific gravity at 60 F. of 0.79, a Saybolt color of 26, which is almost water-white, a naphthene content of to 13 weight per cent and a content of paraflinic hydrocarbons of 87 to 90 weight per cent. The paraflinic hydrocarbons were largely branch-chained. By A. S. T. M. distillation the initial boiling point was 476 F., 50 per cent recovered at 512 F., and the end point was 568 F.

Five moles of the C16 hydrocarbon described was sulfochlorinated in the apparatus described, with a mixture of sulfur dioxide and chlorine gases. After the sulfochlorination was completed to the desired extent, the liquid was flushed with nitrogen to get rid of HCl and residual S02. The reaction mixture was then weighed and found to have increased in weight by 240 grams.

This sulfochlorinated material was then shaken thoroughly with 50 cc. of a 10 weight per cent potassium hydroxide solution ice-cold. The organic layer was separated from the resulting aqueous layer and dried over sodium sulfate. The dried organic material was then treated with adsorptive clay at 60 C., although this step is not essential in obtaining the color stabilization of the present invention.

The thus-treated material remained much lighter in color than an untreated sample of the same material. The untreated sample was black after less than one week. In contrast, the treated material after 14 weeks had a Gardner color of 10, and after a years time was still comparatively light in color and transparent.

Example 2 Normal heptane in the amount of 15 moles was sulfochlorinated as described in Example 1. After blowing the reaction mixture with nitrogen to remove HCl and $02, the material was found to have gained 741 grams in Weight. The resulting heptanesulfonyl chloride was washed with ice water and then with ice-cold 10 per,

cent sodium hydroxide solution. It was then washed with water until the washings came out just slightly alkaline. On storage the thus-treated material underwent no color change over a 6-week period, at the end of which time it was still perfectly clear. In contrast, heptanesulfonyl chloride prepared in exactly the same way changed color overnight. The treated sample on further standing was found to be clear and colorless 13 months after preparation.

Example 3 Cyclohexane in the amount of 19 moles (1596 grams) was found to increase in weight by 888 grams after sulfochlorination as described in Example 1 and nitrogen flushing. The cyclohexylsulfonyl chloride thus made was filtered to remove a slight turbidity caused by the presence of a small amount of solid cyclohexyldisulfonyl chloride. It was then water-washed, washed with ice-cold potassium hydroxide solution (about 5 weight per cent KOH in water), and then dried over sodium sulfate. An alternative method of drying is by distillation. The liquid product analyzed 10.1 weight per cent sulfur, 12.1 per cent total chlorine and 11.4 per cent hydrolyzable chlorine (chlorine directly on sulfur atom). The conversion of cyclohexane to cyclohexylmonosulfonyl chloride was 57.8 per cent. The cyclohexylsulfonyl chloride washed in the manner described with aqueous KOH remained colorless on standing over a years time.

Although the invention is particularly adapted to the treatment of monosulfonyl chlorides, it is also applicable to the color stabilization of higher sulfonyl halides, for example disulfonyl chlorides. When these higher sulfonyl chlorides are normally solids, they can if desired be dissolved in solvents prior to treating with alkaline materials in accordance with the invention.

While the invention has been described herein with particular reference to various preferred embodiments thereof, and examples have been given of suitable proportions and conditions, it will be appreciated that variations from the details given herein can be elfected without departing from the invention in its broadest aspects.

I claim:

1. A method for stabilizing saturated aliphatic and alicyclic sulfonyl halides prepared by the Reed reaction wtih sulfur dioxide and halogen which comprises treating same before color formation occurs with an alkaline material in the presence of water at non-hydrolyzing conditions to inhibit color formation in said sulfonyl halide.

2. A method for stabilizing saturated aliphatic and alicyclic sulfonyl chlorides prepared by the Reed reaction with sulfur dioxide and chlorine which comprises treating same immediately after said preparation with an alkaline material in the presence of water at non-hydrolyzing conditions to inhibit color formation in said sulfonyl chloride.

3. A method according to claim 2 wherein said treating comprises washing said sulfonyl chloride with an aqueous solution of an alkaline material.

4. A method according to claim 3 wherein said aqueous solution is an aqueous solution of an alkali metal compound.

5. A method according to claim 4 wherein said alkali metal compound is an alkali metal hydroxide.

6. A method according to claim 5 wherein said alkali metal hydroxide is potassium hydroxide.

7. A method according to claim 5 wherein said alkali metal hydroxide is sodium hydroxide.

8. A method according to claim 4 wherein said alkali metal compound is sodium carbonate.

9. A method according to claim 1 wherein said alkaline material is an alkali metal compound.

10. A method according to claim 1 wherein said alkaline material is an alkaline earth metal compound.

11. A method according to claim 2 wherein said alkaline material is employed in solid form.

12. A method according to claim 2 wherein a sulfonyl chloride of a parafiinic hydrocarbon is treated.

13. A method according to claim 2 wherein a sulfonyl chloride of naphthenic hydrocarbon is treated.

14. A method according to claim 3 wherein said washing is effected at a temperature below C.

References Cited in the file of this patent UNITED STATES PATENTS 1,906,761 Luthy et al. May 2, 1933 2,046,090 Reed June 30, 1936 2,346,568 Fox Apr. 11, 1944 FOREIGN PATENTS 625,757 Great Britain July 4, 1949 

1. A METHOD FOR STABILIZING SATURATED ALIPHATIC AND ALICYCLIC SULFONYL HALIDES PREPARED BY THE REED REACTION WITH SULFUR DIOXIDE AND HALOGEN WHICH COMPRISES TREATING SAME BEFORE COLOR FORMATION OCCURS WITH AN ALKALINE MATERIAL IN THE PRESENCE OF WATER AT NON-HYDROLYZING CONDITIONS TO INHIBIT COLOR FORMATION IN SAID SULFONYL HALIDE. 